omap_hsmmc: put MMC regulator to sleep
When a card is not in use, the voltage regulator can be put to sleep.
This is an alternative to powering the card off, when powering off is not
safe because the card might be replaced without the driver being aware of
it.
That situation happens if:
- the card is removable i.e. not eMMC
- and there is no card detect
- and there is a cover switch but the cover is open
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: Denis Karpov <ext-denis.2.karpov@nokia.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Philip Langdale <philipl@overt.org>
Cc: "Madhusudhan" <madhu.cr@ti.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 016914c..c82ec7f 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -162,6 +162,7 @@
int response_busy;
int context_loss;
int dpm_state;
+ int vdd;
struct omap_mmc_platform_data *pdata;
};
@@ -1038,10 +1039,12 @@
case MMC_POWER_OFF:
mmc_slot(host).set_power(host->dev, host->slot_id,
0, 0);
+ host->vdd = 0;
break;
case MMC_POWER_UP:
mmc_slot(host).set_power(host->dev, host->slot_id,
1, ios->vdd);
+ host->vdd = ios->vdd;
break;
case MMC_POWER_ON:
do_send_init_stream = 1;
@@ -1179,19 +1182,20 @@
/*
* Dynamic power saving handling, FSM:
- * ENABLED -> DISABLED -> OFF
+ * ENABLED -> DISABLED -> OFF / REGSLEEP
* ^___________| |
* |______________________|
*
* ENABLED: mmc host is fully functional
* DISABLED: fclk is off
* OFF: fclk is off,voltage regulator is off
+ * REGSLEEP: fclk is off,voltage regulator is asleep
*
* Transition handlers return the timeout for the next state transition
* or negative error.
*/
-enum {ENABLED = 0, DISABLED, OFF};
+enum {ENABLED = 0, DISABLED, REGSLEEP, OFF};
/* Handler for [ENABLED -> DISABLED] transition */
static int omap_mmc_enabled_to_disabled(struct mmc_omap_host *host)
@@ -1228,8 +1232,12 @@
mmc_slot(host).get_cover_state(host->dev, host->slot_id))) {
mmc_power_save_host(host->mmc);
new_state = OFF;
- } else
- new_state = DISABLED;
+ } else {
+ if (mmc_slot(host).set_sleep)
+ mmc_slot(host).set_sleep(host->dev, host->slot_id,
+ 1, 0, 0);
+ new_state = REGSLEEP;
+ }
OMAP_HSMMC_WRITE(host->base, ISE, 0);
OMAP_HSMMC_WRITE(host->base, IE, 0);
@@ -1286,6 +1294,44 @@
return 0;
}
+/* Handler for [REGSLEEP -> ENABLED] transition */
+static int omap_mmc_regsleep_to_enabled(struct mmc_omap_host *host)
+{
+ unsigned long timeout;
+
+ dev_dbg(mmc_dev(host->mmc), "REGSLEEP -> ENABLED\n");
+
+ clk_enable(host->fclk);
+ clk_enable(host->iclk);
+
+ if (clk_enable(host->dbclk))
+ dev_dbg(mmc_dev(host->mmc),
+ "Enabling debounce clk failed\n");
+
+ omap_mmc_restore_ctx(host);
+
+ /*
+ * We turned off interrupts and bus power. Interrupts
+ * are turned on by 'mmc_omap_start_command()' so we
+ * just need to turn on the bus power here.
+ */
+ OMAP_HSMMC_WRITE(host->base, HCTL,
+ OMAP_HSMMC_READ(host->base, HCTL) | SDBP);
+
+ timeout = jiffies + msecs_to_jiffies(MMC_TIMEOUT_MS);
+ while ((OMAP_HSMMC_READ(host->base, HCTL) & SDBP) != SDBP &&
+ time_before(jiffies, timeout))
+ ;
+
+ if (mmc_slot(host).set_sleep)
+ mmc_slot(host).set_sleep(host->dev, host->slot_id,
+ 0, host->vdd, 0);
+
+ host->dpm_state = ENABLED;
+
+ return 0;
+}
+
/*
* Bring MMC host to ENABLED from any other PM state.
*/
@@ -1296,6 +1342,8 @@
switch (host->dpm_state) {
case DISABLED:
return omap_mmc_disabled_to_enabled(host);
+ case REGSLEEP:
+ return omap_mmc_regsleep_to_enabled(host);
case OFF:
return omap_mmc_off_to_enabled(host);
default:
@@ -1393,7 +1441,8 @@
host->dpm_state, mmc->nesting_cnt,
host->context_loss, context_loss);
- if (host->suspended || host->dpm_state == OFF) {
+ if (host->suspended || host->dpm_state == OFF ||
+ host->dpm_state == REGSLEEP) {
seq_printf(s, "host suspended, can't read registers\n");
return 0;
}